buffer gets oracle database tuning

full table scan and choose the correct optimization mode: Oracle tuning:the Definitive Reference 3, the SQL adjustment strategy step A lot of people ask SQL tuning where to start. The first thing to do is to capture the SQL statements from the library cache according to their activity status. 1, looking for large impact of the SQL statement We can sort through the number of times the SQL s

Among the many Oracle problems, the most important one is the buffer busy wait (buffer busy wait) event. Buffer busy waiting is the most common phenomenon in the I/O-bound Oracle system, especially in the first five busy (sequential/distributed) read systems in the

Oracle Database 10g Performance Tuning tips and techniques is recommended. For Oracle performance test, diagnosis, analysis, and optimization, see! Chapter 2 Basic index principles (beginner developer and beginner dBA). For Oracle index optimization, refer! Chapter 4

filtering out unwanted records before group by. The following two queries return the same result but the second one is significantly faster.The code is as follows:Low efficiency:SELECT JOB, AVG (SAL)From EMP GROUP job has job = ' president ' and AVG (SAL) >xxxEfficient:SELECT JOB, AVG (SAL)From EMPWHERE JOB = ' President 'OR job = ' MANAGER ' GROUP JOB having and AVG (SAL) >xxx7, usually, if the statement can avoid the use of subqueries, as far as possible without sub-query.Because the overhead

Remote buffer overflow vulnerability in Oracle Database Export exp.exe Parameters Remote buffer overflow vulnerability in Oracle Database "exp.exe" parameter files Release date:Updated on: Affected Systems:Oracle 10gOracle Oracle1

Among the many Oracle-related issues, one of the most important is the buffer busy wait (buffer busy waiting) event. Buffer busy waiting is the most common phenomenon in i/o-bound Oracle systems, especially in the first five busy read (sequential/decentralized) systems repo

; alter system set memory_max_target=7168m Scope=spfile; - theSystem altered. the theSql> alter system set memory_target=7168m Scope=spfile;94 theSystem altered. the theSql> alter system set sga_max_size=4587m Scope=spfile;98 AboutSystem altered. - 101Sql> alter system set sga_target=4587m Scope=spfile;102 103System altered.104 thesql> shutdown Immediate106Database closed.107Database dismounted.108ORACLE instance shut down.109Sql> Startup theORACLE instance started.111 theTotal System Glo

Label:A recent project involves data-table queries of large data volumes. The total data table is about 700 million-2 billion, the primary key to establish a global unique index, the partition policy is hash partition + range partition, most of the time the query condition hit record more than million, a single return to the previous XX record. The following experiences are summed up in the tuning process:(1) Minimize the interval limit, even if the a

Database analysisStatement execute dbms_utility. Analyze_database (' COMPUTE ', Null,null, ');Discovery Table Link LineStatement Select table_name,chain_cnt from User_tables ORDER BY chain_cnt DescSelect table_name,chain_cnt from All_tables where owner= ' RMS ' ORDER by chain_cnt DescCalculate cache Hit RateStatement SELECT Name,value from V$sysstat where NAME in (' physical reads ', ' db block gets ', ' co

(Table Space indent script)] --1, get tablespace information that needs to be freed (contains Oracle database own table space) --drop table System.tbs_detail; CREATE TABLE System.tbs_detail as Select A.tablespace_name, a.bytes/1024/1024 "SUM_MB", (a.bytes-b.bytes)/1024/1024 "USED_MB", b.bytes/1024/1024 "FREE_MB", Round (((a.bytes-b.bytes)/a.bytes) *100,2) "Percent_used" From (select tablespace_nam

Buy Oracle Database Course package and enjoy 85 discount!!Package Address: http://edu.51cto.com/pack/view/id-807.htmlPerformance optimization for Oracle 11g R2 databaseDatabase performance problem is the most discussed topic in database field, because it involves database pr

The newly installed database may need to adjust the Oracle database encoding, otherwise importing data may be an error.oracle11g changing the character set Al32utf8 to ZHS16GBKSQL codeDatabase Character Set (Al32utf8) and Client character set (ZHS16GBK) are different.Character set conversion may cause unexpected results.Note:you can set the client character set t

installation files? Installing the cluster software under the Oracle Grid infrastructure Architecture? Install the database software and create the databaseIV: Managing Oracle DB Instances and RAC databases? Oracle RAC Database management?

Tags: result rom query using combined query execution environment equals on outputThe execution environment of a statement is a SQL window of Plsql, which is intended to determine the number of records not equal to a field from all tables in the entire database.The code is as follows:DECLARE S_sql clob:= "; --Declares a variable that is used to store the SQL statement of the queryV_citycode varchar2 (20); --Each SQL statement executes the query result code VARCHAR2 (20); --Query condition Begin

SQL Server gets the first record in each group In daily life, we often need to record some operations, similar to the operation of the log, the last record is valid data, and maybe they belong to different aspects, functions below, from the terminology of the database, is to find a piece of data in each group. Here's what we're going to do is implement the first piece of data from each group in SQL Server.

, Center_latinnumber,center_lnginnumber) is V_muidsvarchar (200); V_distancenumeric (9,6); BEGIN FORL_RECORDIN (select*fromm_maintenaceunit) LOOP selectgetdistance (L_record. Lat,l_record. LONGITUDE,CENTER_LAT,CENTER_LNG) INTOv_distanceFROMdual; /*dbms_output.put_line (' Distance: ' | | v_distance); */IF (v_distanceBecause of the use of MyBatis, the service invocation is as follows: @Override public listThis is related to the article I reproduced earlier about

C # Gets the SQL statement for the column name and data type of a table in the Oracle database: Select Column_name,data_type, Data_length,data_precision,data_scale from User_tab_ columns [where table_name= table name] Description of this SQL statement: column_name: A table column name (VARCHAR2 ());d Ata_type: The data type of a table column (VARCHAR2 (106)); Dat

("Jdbcurl");user = Properties.getproperty ("user");Password = properties.getproperty ("password");Creating a Driver object from reflectionDriver Driver =(Driver) Class.forName (Driverclass). newinstance ();Properties Info = new properties ();Info.put ("user", user);Info.put ("password", password); Get a database connection through the Driver Connect methodConnection Connection = Driver.connect (Jdbcurl, info);return connection;} @Testpublic void Test

') from dual; CREATE UNIQUE INDEX "Jingyu". " pk_t_part_id "on" Jingyu "." T_part "(" Start_time "," ID ") PCTFREE Initrans 2 Maxtrans 255 STORAGE (buffer_pool default Flash_cache default C Ell_flash_cache DEFAULT) tablespace "Dbs_i_jingyu" LOCAL (PARTITION "P20150101" PCTFREE 2 Initrans Maxtrans L Ogging STORAGE (buffer_pool default flash_cache default Cell_flash_cache default) tablespace "Dbs_i_jingyu", parti tion "P20150102" PCTFREE Initrans 2 Maxtrans 255 LOGGING STORAGE (buffer_pool defaul